In the prior state of the art, the most commonly used pliers are known as groove-joint pliers and slip-mount pliers that are used for gripping and turning. There are also many other special purpose types of pliers, but few, if any, have the gripping power of the instant invention, with the exception of some types of outting pliers. For example, the well-known and widely used groove-joint plier only has approximately a 4.5:1 leverage ratio, and the slip-joint plier approximately a 3:1 ratio. In addition, the applicant's tool operates with constantly parallel jaws at any adjustment position within its capacity. The most popular and commonly used pliers mentioned above have jaws that must be "scissored" in order to grip the workpiece. This scissoring action is also necessary to cover more sizes within the jaw capacity because of the rather limited number of adjustment positions available. This is particularly true as regards the two-position, slip-joint plier and also applies to the groove-joint plier. Further, the handles of groove-joint pliers to not remain in the same relationship lengthwise. When adjusted from maximum to minimum opening, the pivoting handle containing the lower jaw becomes much shorter than the fixed handle because it must slide upward toward the fixed jaw. These Pliers are also difficult to adjust at times due to the fact that the adjustment grooves are not visible to the user and many times the desired adjustment is not obtained in the first try, whereas the adjustment mechanism of the instant invention is in plain sight and can be easily adjusted to the desired setting.
It is also recognized that there are many types of adjustable wrenches that have constantly parallel jaws, but most are not gripping wrenches that close down on and actually grip the workpiece tightly during a turning operation. They must, instead, maintain sufficient clearance so as to be slipped on and off the workpiece in order to turn it--a slow and tedious procedure at best. In addition, there are many times when the operator leaves too much clearance with an adjustable wrench and this fact, coupled with the well-known tendency for the most common adjustable wrench to spread under heavy torque, has earned this tool the unenviable name of "knuckle-buster".